TAMESIS, Colombia – Didier Alvarez shakes his head with fear as he speaks. Over the last decade, he has seen Salgar, his small town in Colombia’s northwest Antioquia province, transformed. In the early 2000s, the leftist Revolutionary Armed Forces of Colombia (FARC) and rival paramilitary units roamed the area, fighting for territory, massacring civilians, and extracting rents from the local economy. By 2008, the armed groups were gone; the FARC was chased into the jungle by the Colombian military and the paramilitaries demobilized. "Things started to calm down," he remembers.

"But we are falling back into crisis," Alvarez continues. "The [FARC] guerrillas and other armed groups are back, destroying our towns, assassinating leaders." Two towns were attacked near his own in the last two months. As the head of the community’s local council, Alvarez is terrified. He’s not the only one; 74 percent of Colombians believe that security is getting worse, according to a June Gallup poll.

Three years ago, the outgoing government of President Álvaro Uribe declared "the end of the end" of the FARC. The group was in its death throes, and this decades-long conflict was coming to an end, Uribe said, thanks to eight years of intensive military operations. But while few seem to be paying attention, this resilient rebel force, which the International Crisis Group estimates has between 8,000 and 10,000 members, has made a comeback — and not only in places like Salgar. In the first six months of 2011, the militant group undertook some 1,115 "military actions," including everything from armed combat to kidnappings to land mining. That’s an increase of 10 percent from the same period last year. In fact, FARC operations have increased every year since 2005.

So is the FARC making a comeback? Not exactly — but it has changed its strategy, according to a report released by the local research institute Corporación Nuevo Arco Iris on July 17. After years of operating like a traditional military organization that fought for territory, carving out large swathes of jungle and terrorizing the outskirts of Colombia’s largest cities, the FARC is going back to its insurgent roots — turning to car bombs, land mines, and high-impact kidnappings. Having lost a number of key leaders and acres of turf to the Colombian military, the group has reorganized into small cells of 25 to 35 people known as pisa suaves, or "light treading" companies of men. These units operate like traditional terrorist cells that might sleep for some time, or infiltrate a community, before they strike.

The result has been a surge in media attention for the FARC. High-profile attacks fill the papers here with increasing frequency. Earlier this month, for example, FARC rebels drove a bus full of explosives into a police station in the southwestern district of Cauca. In late June, attacked a major road in Antioquia, returning to a highway previously thought secure. Such attacks make the local front pages, though they may not be tactically important. As Colombian Armed Forces chief Edgar Augusto Cely argued in March, the guerrillas are fighting "a war of perception."

"There is a new cycle of violence," the report’s author and the director of Arco Iris, León Valencia, told me. "And the government is still in the process of asking: This new stage, what is it? What do we do?"

If the guerrillas have indeed switched tactics in recent years, it is almost certainly out of necessity — an indication of just how effective Colombia’s strategy against the FARC has been. Top guerrilla leaders such as Raul Reyes and Mono Jojoy were killed, and the FARC has been pushed out of the country’s major towns and economic centers." In 2003, the FARC could confront the state for territory. Now, they’ve realized they can’t. And they’re returning to guerrilla tactics," explains Franklin Castañeda, a spokesman for Colombia’s National Victims Movement.

The numbers are indicative. In 2010, the FARC took 110 hostages; this year, it has taken 319 in the first six months alone. The guerrillas have placed land mines in 228 camps so far in 2011, compared with 139 last year. Attacks on vital infrastructure are up too, from 18 in 2010 to 52 between January and June this year. And for the first time, "FARC is using ‘car bombs’ as a military tactic," the Arco Iris report notes, "usually intended at military facilities or urban areas."

The land mines are especially pernicious. Beginning in 2009, the FARC began increasing its use of mines as a means to restrict military patrols, essentially cutting off the armed forces from certain regions and areas. It also cut off thousands of civilians, who were suddenly unable to leave their houses — as well as others seeking to return home, explains Francesca Fontanini of the U.N. High Commission for Refugees.

Shifts in the drug trade have led to parallel shifts by the FARC, which is deeply involved in narcotics trafficking. "Brazil is the second largest consumer of drugs in the world after the United States, and so the cartels are no longer just looking north," he said. "Now they are looking to the south for Brazil — and also for Africa, [a new cocaine route to Europe]." Accordingly, FARC operations are now centered on the country’s southwest. Valencia argues that the center of their operations is now Cali, the country’s third-largest city and one quite close to the Pacific coast.

In urban areas, the guerrillas have begun to form alliances with local criminal bands, known as bacrim. These groups, estimated by the Colombian police in 2010 to have approximately 3,800 members, have infiltrated Colombia’s cities, trafficking everything from drugs to prostitutes to weapons. The International Crisis Group noted last summer that the FARC had made "an extensive network of alliances with other criminal groups" in response to military pressure.

All this clearly represents a new phase in a war that has gone on for decades — and has more than once looked close to its end. This time, it’s not clear whether the government is adapting quickly enough to keep pace with the insurgents.

When he took power in fall 2010, President Juan Manuel Santos promised a new focus on urban security as well as social policies aimed at tackling the very issues that have allowed the FARC insurgency to flourish for so long — poverty, inequality, and longstanding disputes over the distribution of land. He has pushed hard for a "victims’ law," for example, to offer restitution and some compensation to those who have been displaced, injured, or otherwise harmed. He has also gone after Cano with a vengeance, announcing in early July that the FARC leader and strategist had almost been captured. Yet it’s far from clear whether decapitating this organization again would deal it a death blow. As the Arco Iris report put it, "It wouldn’t be wise to create the expectation that the end of this war is coming."

Valencia and his team argue that a better way to combat this new phase of violence would be to add a focus on improving local government to the military strategy. Boosting Colombia’s local institutions, which have long been infiltrated by armed groups seeking to guard their economic and political interests, could be a confidence boost for communities who have come to trust only the law of the jungle. That is truly a long war, however, and the FARC is changing quickly.

Not only that, but this is an election year; votes for local and district offices are scheduled for October. For decades, the FARC has done its best to stage high-profile attacks ahead of the polls, assassinating candidates to demonstrate its enduring power.If history is any guide, the FARC will be preparing to cast its own vote by the gun. The message: We’re down but not out.